Abstract

Because the Carboniferous deposits at Joggins, Nova Scotia, contain the earliest fauna of terrestrial vertebrates, the extremely well-preserved teeth of these ancient animals are of special interest. The " mineral" composition of teeth from the Joggins microsaur Hylerpeton dawsoni is crystallochemically identical with francolite, a carbonate fluorapatite. The fluorine content of the fossilized dentin is 3.1 percent, which is much higher than any previoulsly recorded for fossil teeth.